Related Experiment Video
Updated: Aug 22, 2026
Colorimetric Assessment of Deiodinase 1 Activity in Human Liver Microsomes Using the Sandell-Kolthoff Reaction
Published on: April 10, 2026
Radioiodination, biological distribution, and docking study of diosmetin as a potential radiotracer for infection
Safaa B Challan1, S I Khater2, Hossam M Hassan3
1Labeled Compounds Department, Hot Laboratories and Waste Management Center, Egyptian Atomic Energy Authority, P.O.Box 13759, Cairo, Egypt; Cyclotron Facility, Nuclear Research Center, Egyptian Atomic Energy Authority, P.O.Box 13759, Cairo, Egypt.
Abstract:
Staphylococcus aureus infections, particularly methicillin-resistant strains, pose major diagnostic challenges in differentiating septic from aseptic inflammation. This study aimed to radiolabel diosmetin (3',5,7-trihydroxy-4'-methoxyflavone), a natural flavonoid with antibacterial and anti-inflammatory properties, with iodine-131 (131I) and to evaluate its potential as a radiotracer for infection imaging. Diosmetin was isolated from Rosmarinus officinalis and radiolabeled with Na131I using the chloramine-T method. The radiochemical yield (RCY), and stability were assessed using TLC/HPLC. Molecular docking to COX-2 (PDB: 5KIR) was performed using the MOE software. In vitro binding to S. aureus was measured, and biodistribution studies were conducted in normal, inflamed, and infected Swiss Albino mice (n = 7 per subgroup) at 0.5-3 h post-injection. Target-to-non-target (T/NT) ratios were calculated from the %ID/g values. Radiolabeling achieved 95.8 ± 0.12% yield with >3 h of stability in PBS and serum. Docking revealed a strong COX-2 affinity. In vitro binding to S. aureus reached 52 ± 1.5%. In infected mice, [131I]DSM accumulated selectively in the infected muscle (3.85 ± 0.10%ID/g at 2 h), yielding a T/NT ratio of 7.7, which was double that in inflamed tissue (3.7). Rapid blood clearance, predominant renal excretion, and low thyroid uptake confirmed the in vivo stability. [131I]Diosmetin was prepared with high yield and stability, demonstrated selective uptake at infectious foci, and enabled clear differentiation between septic and aseptic inflammation. These findings support its potential as a promising radiotracer for infection imaging applications.
Insights
This study successfully radiolabeled diosmetin with iodine-131 for infection imaging. The new radiotracer, [131I]diosmetin, shows selective uptake in infected tissues, aiding differentiation of septic inflammation.
Area of Science:
- Nuclear Medicine
- Radiochemistry
- Pharmacology
Background:
- Staphylococcus aureus infections present diagnostic challenges in distinguishing septic from aseptic inflammation.
- Current imaging methods may lack specificity for infection detection.
Purpose of the Study:
- To radiolabel diosmetin (a natural flavonoid) with iodine-131.
- To evaluate [131I]diosmetin as a potential radiotracer for infection imaging.
- To assess its ability to differentiate septic from aseptic inflammation.
Main Methods:
- Diosmetin was isolated and radiolabeled with iodine-131 using the chloramine-T method.
- Radiochemical yield, stability, and in vitro binding to S. aureus were assessed.
- Molecular docking to COX-2 and biodistribution studies in mice were performed.
Main Results:
- High radiochemical yield (>95%) and stability (>3 hours) were achieved for [131I]diosmetin.
- Selective accumulation in infected muscle tissue was observed in mice, with a high target-to-non-target ratio (7.7).
- [131I]diosmetin effectively differentiated septic from inflamed tissues.
Conclusions:
- [131I]diosmetin can be prepared with high yield and stability.
- The radiotracer demonstrates selective uptake at infectious foci.
- [131I]diosmetin shows promise as a novel radiotracer for infection imaging.
